1. Technical Field
The present invention relates to an image forming apparatus and an image forming program.
2. Related Art
In an electrophotographic printer for printing out print data, in the case of performing a full color printing etc. by using the three primary colors CMY (C: cyan, M: magenta, Y: yellow), it is possible to use a color called process black which is formed by mixing all the three primary colors to thereby reduce the brightness.
The process black is used when the black toner (K: black) is not installed in a development machine, when the black toner is run out, or when black is used for a particular usage such as a digital water mark and so the full color printing is performed by other three primary colors CMY.
That is, the process black is used in the case of printing image data, which can be drawn by the black toner, by superimposing three colors. In the case of printing image data on a print medium such as a print sheet by using the process black generated by superimposing the three colors, defects such as the blur of characters, a transfer failure, a fixation failure, ghost likely occur.
In general, transfer failure, fixation failure, degradation of color and color shading likely occur when the total amount of the toner (also called as “pile height”) used for superimposing the respective colors CMY increases. In contrast, when the total amount of the toner reduces, the printed image is likely rubbed and the wobbling of characters becomes striking.